The present invention relates to an automatic transmission, and particularly relates to a structure of a multi-plate clutch.
Recently, the automatic transmission for a vehicle with a multi-speed shift, such as a six forward speeds or more, has become popular. Accordingly, the number of parts of a transmission gear mechanism comprised of planetary gears, brakes, clutches and the like has increased. U.S. Patent Application Publication No. 2004/0248684 A1, for example, discloses an automatic transmission with two sets of multi-plate clutches.
The increase of the number of parts causes a large size of the automatic transmission. Meanwhile, the compactness of the automatic transmission has been demanded from a vehicle layout standpoint. The above-described publication discloses the automatic transmission in which two sets of multi-plate clutches are provided side by side along its radial direction. In this case, while its axial-direction length (size) of the automatic transmission can be properly shortened, it may be difficult to make its radial-direction size compact.